1. Field of the Invention
The present invention relates to the field of naturally occurring colorants and chemicals from plants, including genetically modified and cross-pollinated plants, the provision of colorant and chemicals from plants having high levels of specifically desirable colorants and chemicals, and particularly to corn species that provide significant levels of anthocyanins in products from the corn.
2. Background of the Art
Polyphenols are those compounds which comprise more than one phenolic group. Among the polyphenols are the following classes: flavonoids (a term often used to denote polyphenols in general, but more commonly in Europe to denote only the flavones), the flavanols, proanthocyanidins (also called procyanidols, procyanins, procyanidins and tannins) and anthocyanins.
The flavones are compounds with a basis structure in which two benzene rings (A and B) are linked with a heterocyclic six member ring C containing a carbonyl ring. Ring B can be joined in position 2 to give a flavone or to position 3 to give an iso-flavone. Hydroxylation can occur at positions 3, 5, 7, and 3′, 4′, 5′ to give compounds called flavonols. Typical examples of flavonols are: quercetin (hydroxylated at positions 3, 5, 7, 3′, 4′), kaempferol (hydroxylated at positions 3, 5, 7, 4′) and myricetin (hydroxylated at positions 3, 5, 7, 3′, 4′, 5′). They can exist naturally as the aglycone or as O-glycosides (e.g. D-glucose, galactose, arabinose, rhamnose, etc). Other forms of substitution such as methylation, sulfation and malonylation are also found.
The two most common flavanols are catechin (hydroxyl group positions 5, 7, 3′, 4′) and its stereo-isomer epicatechin. The hydroxyl groups can be esterified with gallic acid. The proanthocyanidins are polymers of catechin and/or epicatechin and can contain up to 8 units or more. These compounds are often called proanthocyanidins, procyanidins or tannins.
The anthocyanins are colored substances, sometimes called anthocyanidins. Typical examples are: cyanidin (hydroxylated at positions 3, 5, 7, 3′, 4′), delphinidin (hydroxylated at positions 3, 5, 7, 4′, 5′) and pelargonidin (hydroxylated at positions 3, 5, 7, 3′). The hydroxyl groups are usually glycosylated and/or methoxylated (e.g. malvidin at 3′, 5′). Within the general term, “polyphenols” are compounds including the dihydroxy-or-tri-hydroxy benzoic acids and the phytoalexins, a typical example of which is resveratrol.
The goal of field crop breeding is to combine various desirable traits in a single variety/hybrid. Such desirable traits include greater yield, better stalks, better roots, resistance to insecticides, herbicides, pests, and disease, tolerance to heat and drought, reduced time to crop maturity, better agronomic quality, higher nutritional value, uniformity in germination times, stand establishment, growth rate, maturity and fruit size.
Breeding techniques take advantage of a plant's method of pollination. There are two general methods of pollination: self-pollination and cross-pollination. A plant self-pollinates if pollen from one flower is transferred to the same or another flower of the same plant. A plant cross-pollinates if pollen comes to it from a flower on a different plant.
Corn plants (Zea mays L.) can be bred by both self-pollination and cross-pollination. Both types of pollination involve the corn plant's flowers. Corn has separate male and female flowers on the same plant, located on the tassel and the ear, respectively. Natural pollination occurs in corn when wind blows pollen from the tassels to the silks that protrude from the tops of the ear shoot.
Plants that have been self-pollinated and selected for type over many generations become homozygous at almost all gene loci and produce a uniform population of true breeding progeny, a homozygous plant. A cross between two such homozygous plants produces a uniform population of hybrid plants that are heterozygous for many gene loci. Conversely, a cross of two plants each heterozygous at a number of loci produces a population of hybrid plants that differ genetically and are not uniform. The resulting non-uniformity makes performance unpredictable.
The development of uniform corn plant hybrids requires the development of homozygous inbred plants, the crossing of these inbred plants, and the evaluation of the crosses. Pedigree breeding and recurrent selections are examples of breeding methods used to develop inbred plants from breeding populations. Those breeding methods combine the genetic backgrounds from two or more inbred plants or various other broad-based sources into breeding pools from which new inbred plants are developed by selfing and selection of desired phenotypes. The new inbreds are crossed with other inbred plants. The hybrids from these crosses are evaluated to determine which of those have commercial potential.
North American farmers plant tens of millions of acres of corn at the present time, and there are extensive national and international commercial corn breeding programs. A continuing goal of these corn breeding programs is to develop corn hybrids that are based on stable inbred plants and have one or more desirable characteristics. To accomplish this goal, the corn breeder must select and develop superior inbred parental plants.
Published U.S. Patent Application 20080047028 (Cook) provides seed and plants of the corn variety designated CV414351. The invention thus relates to the plants, seeds and tissue cultures of the variety CV414351, and to methods for producing a corn plant produced by crossing a corn plant of variety CV414351 with itself or with another corn plant, such as a plant of another variety. The invention further relates to corn seeds and plants produced by crossing plants of variety CV414351 with plants of another variety, such as another inbred line. The invention further relates to the inbred and hybrid genetic complements of plants of variety CV414351. Low levels of anthocyanins are reported.
U.S. Pat. No. 6,767,999 (Smirnov et al.) describes anthocyanin colorant made from corn pulp and a process for its production which relates to food, cosmetic, pharmaceutical and textile industries and which may be used in coloring edible or ingestible products. The components percentage shall be as follows: cyanidin glycoside 0.1-8.6%; peonidin glycoside 0.08-6.45%; pelargonidin glycoside 0.005-4.3%; organic substances and mineral salts are the remaining materials. Due to the fact that the colorant solution contains pelargonidin glycoside further to cyanidin and peonidin glycosides, the proposed colorant obtained expanded the color spectrum. Combination of these three anthocyanins in the proposed colorant provides for a rich spectrum of red colors. The colorant retains red color when pH of the environment is not more than 7. It is thermostable, photostable and maintains its properties during two years. Besides, its relative optical density is the highest when it is subjected to the light with wavelength of 505-515 nm. According to the invention, process of the colorant production implies that pre-dried vegetable maize-pulp containing anthocyanins is ground, extracted by a mix of aqueous solutions of hydrochloric and citric acids in the field of ultrasonic vibration. Then the extracted coloring matter is filtered and concentrated in vacuum. The primary material is additionally prepared for extraction by infusion of grinded (ground) material in extracting agent during 6-8 hours at the temperature of 35-40° C. Extraction may be performed in three steps. Processing for extraction of each lot shall be 30-40 minutes at the temperature of 35-40° C. The process makes the production technology easier and provides for additional source of primary materials.
Various processes have been developed for the extraction of anthocyanins from fruits, vegetables and grains, especially from grapes. Various methods have been developed to extract polyphenols from grape skins, especially from red or black grapes, since the anthocyanin pigment is used as a colorant in foods.
Yokoyama et al. (U.S. Pat. No. 4,302,200) discloses a process for extracting anthocyanin-type color from natural products (grapes) which includes contacting the natural product with a sulfite ion-containing aqueous solution at a temperature of about 85° C. or higher.
Hilton et al. (U.S. Pat. No. 4,320,009) discloses a process for obtaining anthocyanin pigment extracts in which large quantities of anthocyanin extract may be obtained from grape skin residue from wine fermentation.
Shrikhande (U.S. Pat. No. 4,452,822) discloses a process for improvements in the production of anthocyanin coloring material from red grape pomace or other anthocyanin sources using extraction with sulfur dioxide.
Crosby et al. (U.S. Pat. No. 4,481,226) discloses a stabilized anthocyanin grape extract colorant. The stabilized product is made by combining tannic acid and anthocyanin grape extract colorant in an appropriate solvent and recovering the product.
Langston (U.S. Pat. No. 4,500,556) discloses a process for obtaining anthocyanin colorant by extraction from grape pomace. The method described in Langston is to contact grape pomace with HSO3 to form a complex. The complex is recovered by treating the liquid extract phase with a non-ionic adsorbent to adsorb the complex.